Air getting under student's goggles, probably making it harder to see, diminishing the value of the jump she paid for. Instructor might have done better to ensure the goggles were tight & properly placed, but it could be due to using Kroops, as they are notorious for having crappy elastics that wear out quickly.

"The benefits of providing tandem students with altimeters greatly outweigh the minimal additional costs. Training students thoroughly for their skydives, including information on how to check altitude, can only improve the overall safety of skydiving for both students and instructors. Student altimeters provide valuable back-up for instructors if their altimeters fail, and using them allows students to become active participants in their jumps."

"The benefits of providing tandem students with altimeters greatly outweigh the minimal additional costs. Training students thoroughly for their skydives, including information on how to check altitude, can only improve the overall safety of skydiving for both students and instructors. Student altimeters provide valuable back-up for instructors if their altimeters fail, and using them allows students to become active participants in their jumps."

—Jim Crouch | D-16979 USPA Director of Safety & Training

That quote must be from before he backed the BOD when they deleted the requirement on Tandem Student to have a Altimeter, and before he started saying to many that the Alti on the T-I was "available" for the Student if need be.